Low idle problem when in gear and brake is applied while stopped

[SkiMilly97]

I have a 2006 3 base model i mean bottom of the barrel. I have had way to many problems to list since the day i drove it off the lot new. 7 times the car shutdown while driving on the highways 7 times the dealership turned the other well after other problems called up 1800lemonlaw and mazda paid me 7000 to shutup and they would not report it as a lemon. well still have the pos and never solved the idling problem when im in gear and sitting at a light or stop sign. the idle drops significantly and causes the engine to shutter feels like the engine wants to die but never does other than that no real issues observed in any other conditions so if anyone knows of any solutions please do tell. i am a mechanic not by trade but i know my cars but this one i have never dove into it. please help!